ML20072V407

Forwards YAEC-1698, Analysis of Postulated Design Basis Steam Generator Tube Rupture for Seabrook Nuclear Power Station

ML20072V407
Person / Time
Site:	Seabrook
Issue date:	04/16/1991
From:	Feigenbaum T PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20072V410	List: ML20072V407 ML20072V423
References
NYN-91061, NUDOCS 9104220185
Download: ML20072V407 (3)

Text

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• New Hampshire Yankee e t--

Chief Executive Olheer NYN 91061 April 16,1991 United States Nuclear Regulatory Commi<sion Washington, D.C. 20555 Attention: Document Control Desk

References:

(a) Facility Operating License No. NPF 86, Docket No. 50-443 (b) NilY Letter SI3N 891, dated November 13,1985

• Plant Performance During a Steam Generator Tube Rupturet Outstanding issue No.17, Licensing Condition No.18" J. DeVincentis to USNRC 4

(c) USNRC Safety Evaluation Rcport Related to the Operation of Seabrook Station Units 1 and 2 NUREG 0896, March 1983 (d) USNRC Safety Evaluation Report Related to the Operation of Seabrook Station Units 1 and 2, NUREG 0896 Supplement No. 4, May 1986

Subject:

Analysis of a Postulated Design llasis Steam Generator Tube Rupture for Seabrook Station Gentlemen:

New Hampshire Yankee committed in Reference (b) to perform a plant specific Steam l Generator Tube Rupture (SGTR) analysis _ and to submit such analysis prior to startup following the first refueling outage. The NRC found this schedule to'be acceptable as stated j in Reference (d) and determined that SGTR should be recategorized as a Confirmatory issue

( # 45),

in fulfillment of NHY's commitment, a -plant specific design basis SGTR - analysis report has been prepared and is enclosed herein for NRC review. The enclosed report entitled " Analysis Of A Postulated Design Basis Steam Generator Tube Rupture For The ,

Seabrook Nuclear Power Station' was prepared by Yankee Atomic Electric Company for j NHY. Yankee Atomic Electric Company personnel have been active participants in the Westinghouse Owners Group (WOG) SGTR subgroup of utilities which was formed in 1983 to address NRC questions regarding the adequacy of SGTR analyses. The WOG subgroup developed and submitted for NRC review a new SGTR analysis methodology and results for a reference plant.

9104220185 910416 PDR P

ADOCK 05000443 -

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(j 1 New Hampshire Yonkee Division of Public Service Company of New Hampshire yg

- .I., bsM-e- r g 4 - P.O. Box 300

• Seabrook, NH 03874

• Telephone (603) 474 9521- I

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6 United States Nuclear Regulatory Commission April 16,1991 Attention: Document Control Desk Page two The WOG SGTR subgroup methodology was subsequently approved by the NRC with the requirement that each subgroup member submit a plant specific analysis that includes the following elements:

Simulator demonstration runs to support the operator action times used in the plant specific analysis since the new analysis methodology credits operator action to mitigate the consequences of a design basis SGTR.

- An evaluation of the structural adequacy of the main steam lines and associated supports under water filled conditions is required even though the reference plant analysis demonstrated margin to steam generator overfill and acceptable radiation releases in the unlikely event that steam generator overfill did occur.

A listing and safety classification of the systems, components, and instrumentation credited for SGTR mitigation in the plant specific Emergency Operating Procedures (EOPs).

Demonstration of the plant specific applicability of all assumptions used in the analysis.

Each of the above elements is addressed in the enclosed report. The computer codes and some of the assumptions employed in this report differ from those in the NRC approved methodology, however the methodologies are fundamentally equivalent and all differences are described and justified.

The enclosed plant specific SGTR analysis provides the following conclusions:

Analysis results demonstrate that overfill of the faulted steam generator is not expected to occur. Nevertheless, a static load analysis of flooded main steam lines has been performed, as required by the NRC, demonstrating that the lines will remain intact in this highly unlikely consequence of a SGTR; The off site radiological doses received at the exclusion area boundary and the l low population zone boundary would be within the limits of 10CFR100 a-3 J..e Standard Review Plan (SRP) guideline values; l

No plaut design changes are required to support the analysis. Systems,-

components and instrumentation credited in the analysis for mitigation of the i design basis SGTR are nuclear safety related, or are specifically noted and justified, and meet the single failure criteria for the required function.

The existing FSAR description of the SGTR analysis will be revised to reflect the i enclosed plant specific SGTR analysis subsequent to completion of NRC review. '

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United States Nuclear Regulatory Commission April 16,1991 Attention: Decument Control Desk Page three Please direct any questions regarding this letter to Mr. James M. Peschel, Regulatory Compliance Manager at (603) 474 9521, extension 3772.

Very truly yours, A W ll Ted C. Fei enbaum Enclosure; ' Analysis Of A Postulated Design Basis Steam Generator Tube Rupture For The Seabrook Nuclear Power Station' YAEC.1698, A.E. Ladieu et al.

TCF:ALL/ssi/act cc: Mr. Thomas T. Martin Regional Administrator United States Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Mr. Gordon E. Edison, Sr. Project Manager Project Directorate 13 Division of Reactor Projects U.S. Nuclear Regulatory Commission Washington, DC 20555 Mr. Noel Dudley NRC Senior Resident inspector

! P.O. Box 1149 l Seabrook, NH 03874 l

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e New Hamphire Yankee April 16,1991 ENCLOSURE TO NYN 91061 P

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